Snap acting switch



June 2, 1964 N. MILLER 3,135,841

SNAP ACTING SWITCH Filed Aug. 18, 1959 3 Sheets-Sheet l [HVEHXUPNICHOLAS M/LLEE- DEC. 5) DOA/ALB E M/LLEE E0852 E M/LLEE EXECS.

June 2, 1964 .N. MILLER 3,135,841

SNAP ACTING SWITCH Filed Aug. 18, 1959 5 Sheets-Sheet 2 June 2, 1964 N.MILLER 3, ,8

SNAP ACTING SWITCH 3 Sheets-Sheet 3 Filed Aug. 18, 1959 F'z 5 j a B)DONALD E. M/LLEP EOGEE E M/LLE,Q EIXEC'S. EU M fijj 5.

, zmg 'izqa r United States Patent SNAP ACTING SWITCH Nicholas Miller,deceased, late of Chicago, Ill, by Donald E. Miller, Mount Prospect, andRoger F. Miller, Chicago, 111., coexecuters, assignors to The Dole ValveCompany, Morton Grove, Ill., a corporation of Illinois Filed Aug. 18,1959, Ser. No. 834,451 2 Claims. (Cl. 209-67) This invention relates tosnap action mechanisms and more particularly relates to a double throwsnap action mechanism having a neutral or off position.

Snap action mechanisms have found great utility in recent years sincethey are relatively simply and economically manufactured and since theyare operable to actuate the mechanism with which they are associatedwith a positive stroke of the snap blade even though the force whichacts to actuate the mechanism is applied very slowly. More particularlysuch snap action mechanisms have found particular utility in theelectrical field in the form of double throw snap action switches s'uicethe quick snapping action of the snap blade associated with themechanism is efllective to substantially eliminate arcing between twoadjacent contacts.

Heretofore, however, such snap action mechanisms have been simply of thesingle or double throw type having no provision for maintaining the snapblade associated with the mechanism in an intermediate P sit on- Thoseskilled inthe art of designing and using snap action mechanisms andparticularly those acquainted with the adaptability of same to theelectrical field will recognize the desirability of providing a snapaction mechanism having a neutral or oil position so that, in essence, atriple throw rather than the usual double throw switch is provided.

The invention relates to a switch mechanism wherein the snap bladeassociated with the mechanism is movable to any one ofthree selectedpositions as desired. Two embodiments of such a mechanism are hereafterset forth and described with particulartiy and illustrated in theappended drawings.

In the first embodiment of the invention, the snap action mechanism isshown as comprising generally a mounting plate upon which are afiixedtwo transversely spaced electrical contacts which have a movable contactdisposed therebetween. The movable contact is snapped into engagementwith one or the other or the two stationary contacts by the usualactuator lever and overcenter spring but has an abutment memberassociated therewith which is connected to the actuator lever and whichis ellective to hold the movable contact out of engagement with one ofthe stationary contacts in one position of the actuator lever. Upondepressional movement of the actuator lever the movable contact, whichis initially disposed in engagement with the lower of the two stationarycontacts is snapped upwardly into engagement with the upper of the twostationary contacts. Upon further depressional movement of the actuatorlever, however, the abutment member which is connected to the actuatorlever and which is engageable with the movable contact movesinto'engagement with the movable contact to move the same out ofengagement with the upper of the two stationary contacts. Since,however, the movable contact is not moved by the abutment member to aposition past the overcenter position of the overcenter spring themovable contact is not thereby snapped into engagement with the lower ofthe two stationary contacts but is, rather, held in an intermediate orneutral position between the two stationary contacts.

The second embodiment of the invention functions on substantially thesame principles but in this embodiment depressional movement of theactuator lever acts to first move the movable contact which is initiallyin engagement with the lower of the two stationary contacts into anintermediate position and, thereafter, further depressional movementacts to permit spring urged movement of the movable contact intoengageemnt with the upper of the two stationary conta ts. Thus, in thefirst embodiment of the invention, the intermediate or neutral positionor" the movable contact or snap blade is effected after the actuatorlever has been depressionally moved to its fullest extent. On thecontrary, in the second embodiment of the invention the neutral orintermediate position of the movable contact or snap blade is effectedin an intermediate pivoted position of the actuator lever.

It is, of course, to be understood that such snap action switchmechanisms as are hereinafter disclosed in detail may find utility inother instances than in the electrical field since triple throw switchesmay, for instance, be used in controlling the movement of a spool valveor the like.

It is therefore a principal object of the present invention to provide asnap action mechanism in which the snap blade associated therewith maybe controllably moved to any of three separate positions.

A further object of the invention is to provide a snap action mechanismof the type above described which may be readily and economicallymanufactured.

Another important object of the invention is the provision of a snapaction mechanism wherein the snap blade associated therewith may bemoved to any of three separate positions as desired and wherein movementof the snap blade to these respective positions is elfected as afunction of the degree of movement of the usual actuator leverassociated therewith.

These and other objects of the invention will appear from time to timeas the following specification proceeds and with reference to theaccompanying drawings, where- FIGURE 1 is a partially sectionalpartially elevational view of a snap action mechanism constructed inaccordance with the principles of the present invention and showing thesnap blade or movable contact in a first position;

FIGURE 2 is a partially sectioned partially elevational view which issimilar in nature to FIGURE 1 but which shows the snap blade inengagement with the other of two opposed electrical contacts;

FIGURE 3 is a partially sectional partially elevational view which issimilar in nature to FIGURES 1 and 2 but which shows the snap blade inan intermediate position;

FIGURE 4 is a fragmental partially sectioned partially elevational viewof the snap action mechanism illustrated in FIGURES 1-3 which is takenalong lines IVIV of FIGURE 1;

FIGURE 5 is a partially sectioned partially elevational View of a secondembodiment of the snap action mechanism of my invention showing themovable contact in a first position;

FIGURE 6 is a view similar in nature to FIGURE 5 but which shows themovable contact in an intermediate position; 7

FIGURE 7 is a view similar to FIGURES 5 and 6 which shows the movablecontact in engagement with the other of the two opposed stationarycontacts;

FIGURE 8 is a partially sectioned partially elevational view of the snapaction mechanism illustrated in FIG- URES 57 which shows the mechanicaltransducer in side elevation and which is taken along lines V[[[V]I[ ofFIGURE 5; and

FIGURE 9 is a view which is similar in nature to FIGURE 8 but whichshows the mechanical transducer in a difierent position from thatillustrated in FIGURE 8 and which is taken along lines IXD( of FIGURE 7.

, V In the embodiment of the invention illustrated in FIGURES l-4, asnap action mechanism is shown by way of example, and not by way oflimitation, being adapted for. use as a double throw electrical switchmechanism and includes generally a snap or actuator lever 11, a snapblade or movable contact 12, and an overcenter spring 13 interconnectingthe free end portions of the lever 11 and the blade 12. A supportingmember or plate 14 serves to mount the various parts of the snap actionmechanism and has an L-shaped bracket 15 mounted adjacent one endthereof which, in turn, serves as a mounting means for the actuatorlever 11 and the snap blade 12. The bracket 15 is apertured at the upperend thereof to receive one end of the actuator level 11. The lever 11has its end which is disposed adjacent the aperture in the bracket 15turned downwardly as at 16 to prevent movement of the lever out of theaperture by the overcenter spring 13. The free end of the lever 11 has adownwardly turned arm 17 formed integrally therewith which is bent toform a recess 18 adjacent the lower end thereof.

The snap blade 12 is secured to the base portion of the L-shaped'bracket 15 by means of a rivet 19 and has its outer free end connectedwith the depending arm 17 of the lever 11 by means of the overcenterspring 13.

disposed within the recess 18 in the depending arm 17 and has itsopposite end portion received within a spring retaining cup 20. Thespring retaining cup 20 has a recess 21 formed within the outer surfacethereof which is adapted to receive the free end of the snap blade 12.

A pair of transversely spaced electrical connecting tabs 23 and 24 aremounted within suitable apertures on the supporting plate 14 and havecontacts 25 and 26, respectively, mounted therein. Obviously, where thesnap action switch mechanism is being used as an electrical switch itwould be necessary to form the supporting plate 14 of some insulatingmaterial. The connecting tabs 23 and 24 each have protruding legs 27 and28, respectively, ex-

tending rearwardly from the supporting plate 14 which are adapted to beconnected to electrical power transmission lines. Thus, by connectingthe bracket 15 to the opposite side of an electrical power line acurrent may be transmitted through the tab 27 or the tab 28 as desiredby merely moving the snap blade 12 into engagement with one or the otherof the two contacts 25 and 26.

As is well known in the art the snap blade 12 is moved into contact withone or the other of the two stationary contacts 25 and 26 as a functionof the position of the actuator level 11. Thus, when the actuatorlever11 is in an extreme clockwise rotated position such as is shown inFIGURE 1, the overcenter spring 13 acts to urge the snap blade 12 intoengagement with the lower stationary contact 26. When the point ofcontact of spring 13 with the actuator lever 11 is moved to a pointbelow the point of contact of the spring retainer 20 and the blade 12 bydepressional movement of the actuator lever 11, the overcenter spring 13acts to snap the blade 12 out of engagement with the lower stationarycontact 26 and into engagement with the upper stationary contact 25 thusopening the circuit through the tab 28 and closing the electricalcircuit through the tab 27.

It will here be noted that depressional movement of the actuator lever11 may be effected by means of a plunger 30 such as is illustrated inthe drawings or in any other suitable manner. In this regard it will beunderstood that the plunger 30 may be'connected to the actuator lever11'so that upward movement of the plunger Will act to return theactuator lever 11 and its associated parts to the position illustratedin FIGURE 1 or that the plunger 30 and/ or the lever 11 may be providedwith suitable spring means operable to normally bias the various partsofthe snap action mechanism to the position illustrated in FIGURE 1. Themeans 'foreffecting pivotal movement of a the actuator lever 11 do not,however, form a part of the 7 The overcenter spring 13 has one outturnedend portion present invention and so will not herein further bedemechanisms are generally so arranged that the snap blade is onlymovable to one of two opposed positions. The invention, however, relatesto a switch mechanism wherein the snap blade may controllably be held inan intermediate position between the two opposed stationary contacts 25and 26. Toeifect this desirable feature, an abutment member 31 isdisposed in sliding contact with the supporting member 14 and has a pairof opposed convex lips 32 and 33 which are adapted to snugly engage theactuator lever 11. A nib 36 extends rearwardly from member 31 and slideswithin a slot 37 formed in the'member 14 to guide the member 31 throughits path of movement in a vertical plane. An integral depending leg 34of the abutment member 31 extends through a guide slot 35 in theconnecting tab 27 to act as a further guide for the member 31 and isengageable with the snap blade 12 to hold the same out of contact withthe stationary contact 25. A rearwardly extending tab 36 is also formedintegrally with the abutment member '31 and is slidable within alongitudinal guide slot 37 formed in the supporting member 14.

As a result of the configuration of the abutment member 31 and itscooperation with the actuator lever'11 depressional movement of thelever from the position illustrated in FIGURE 2 to the positionillustrated in FIG- URE 3 will beelfective to move the abutment member31 into engagement with the snap lever 12 and to subsequently move thesnap lever out of engagement with the stationary contact 25. n

In operation the snap action mechanism which is illustrated in FIGURES1-4 functions substantially as follows: Assuming that the actuator lever11 is initially in the position illustrated in FIGURE 1, the snap blade12 will be maintained in contact with the stationary contact 26 by thebiasing force of the overcenter spring 13 so that the electrical circuitthrough contact 26'will be closed. Depressional movement of plunger 30will act to pivotally move the actuator lever 11 with respect to thebracket 15 to effect compression of the overcenter spring 13. When thepoint of contact of the overcenter spring 13 with the actuator lever 11has moved to a point below the point of contact of the spring retainer20 with the snap blade 12, the overcenter spring will act to snap theouter free end of the blade 12 upwardly out of engagement withthecontact 26 and into engagement with contact 25..

Further depressional movement of plunger 30 will act to furtherpivotally move the actuator lever 11 in a counterclockwise directionabout the bracket 15 thereby moving 'the abutment member 31 intoengagement with the snap blade 12 and subsequently moving the free endof the snap blade 12 out of. engagement with stationary contact 25.Accordingly, the free end of the snap blade 12 will simply be held bythe abutment member 31 in an intermediate position between thestationary contacts 25 and 26 so that 7 an electrical energizing circuitthrough each of the contacts will at the same time be opened.

In order to maintain the various interconnected parts in an operativerelation with respect to one another, I provide a stop 35a on thesupporting member 14 for limiting pivotal movement of the actuator lever11. The stop 35a has upper and lower outwardly extending arms 36a and37a formed integrally therewith and embracing the actuator lever 11which are adapted to limit the degree of pivotal movement of the lever.

Referring now more particularly to the embodiment of the inventionillustrated in FIGURES 5-9, a snap action switch mechanism is shownwhich is somewhat similar to the embodiment of the invention illustratedin FIGURES 1-4 (like parts having like numerals) but in which the meansfor holding the snap blade 12 in a neutral position differ somewhat. Inthis embodiment of the invention the switch mechanism is so constructedthat depressional movement of the plunger 30 acts initially to move thesnap blade to an intermediate position whi-e further depressionalmovement of the plunger acts to move the free end of the snap blade 12into engagement with the upper stationary contact 25. Thus, the cycle ofmovement of the snap blade is different from that which is effected bymeans of the mechanism illustrated in FIGURES 1-4.

As shown especially in FIGUES 8 and 9, a mechanical transducer 50 issubstituted in place of the abutment mem ber 31 for holding the snapblade 12 in a neutral position and functions on a different principle. Amounting bracket 51 is rigidly secured to the supporting member 14 andhas an apertured outwardly extending flange 52 formed integrallytherewith. A pivot pin 53 extends through the aperture in outturnedflange 52 and is adapted to rotatably receive the apertured ripper arm54 of the mechanical transducer 50. A friction spring 53a is disposedintermediate the head 53b of the pin 53 and the transducer 50 whichfricticnally engages the transducer 50 to retard pivotal movementthereof. The mechanical transducer 50 also has a lower arm 55 formedintegrally therewith which, in turn, has a depending abutment leg 56extending therefrom which is adapted to engage the outer free endportion of the snap blade 12.

It will be understood that the mechanical transducer 50 is so formedthat, when the transducer is in the position illustrated in FIGURE 8,the inner edge of the upper arm 54 extends substantially horizontallywhile the 111L161 edge of the lower arm 55 extends angularly upwardlytoward the outer end of the arm forming a cam face for reasons whichwill hereinafter become apparent. The actuator lever 11 is adapted to bedisposed in the space intermediate the upper and lower arms 54 and 55,respectively, of the mechanical transducer 50 and the end portions ofthe arms are so spaced from one another that the lever has limitedrelative freedom of movement between the arms. That is, the distanceintermediate the outer end portions of the respective arms of themechanical transducer is so fixed that the lever 11 can move from theposition illustrated in full lines in FIGURE 8 to position A illustratedin broken lines therein without caus ng pivotal movement of thetransducer 50. It will be understood that the position of the actuatorlever 11 which is shown in full lines in FIGURE 8 is the same positionof the lever as is shown in FIGURE 5 and that position A of the lever isthe same as the position of the lever shown in FIG- URE 6.

The inclined inner edge of the lower arm 55 acts as a cam surface sothat when the lever 11 is depressionally moved from position A in FIGURE8 to position B therein, the mechanical transducer 50 will be pivotallymoved about the pin 53 to the position illustrated in FIGURE 9.Depressional movement of lever 11 is limited by means of a stop arm 58formed integrally with the bracket 51 and upward movement of the leveris similarly limited by a projecting portion 59 of the bracket 51.

When the actuator lever 11 is in the position illustrated in FIGURE 5and in full lines in FIGURE 8, the snap blade 12 will be positioned withits outer free end portion in engagement with the lower stationarycontact 26 and will be positioned relative to the depending leg 56 ofthe transducer 50 as indicated in full lines in FIGURE 8. Depressionalmovement of the plunger 30 will act to pivotally move the actuator lever11 in a counterclockwise direction about the bracket 15 to an overcenterposition with respect to the point of engagement of the spring retainerwith the snap blade 12 so that the blade 12 will be snapped upwardly outof engagement with the stationary contact 25. The snap blade will not,however, move into engagement with the upper stationary contact but willbe held in an intermediate position between the two opposed stationarycontacts by means of the depending abutment member 56 since it will atthat point be disposed in the path of movement of the blade 12. Furtherdepressional movement of the plunger 30 will act to still further movethe actuator lever 11 in a counterclockwise direction about the bracket15 until it moves into engagement with the stop arm 58. Such movement ofthe lever 11 from position A to position B as shown in FIGURE 8 will actagainst the inclined cam surface of the mechanical transducer 50 topivotally move the transducer in a counterclockwise direction about thepin 53 thereby moving the abutment member 56 out of engagement with thesnap blade 12 and permitting upward movement of the outer free end ofthe snap blade 12 into engagement with the upper of the two opposedstationary contacts 25 as is clearly shown in FIGURES 7 and 9.

As hereinbefore mentioned, it is important to note that such a snapaction mechanism may find great utility in other fields than theelectrical field such as, for instance, where a snap action mechanism isto be associated with a fluid control valve to control the movement of aspool valve or the like.

Also, as a matter of interest, movement of the plunger 30 may beeffected by means of a thermally sensitive power element and in suchcase the plunger 30 might comprise the power member or piston of thethermally sensitive element which is extensible from the body of thepower element upon fusion or expansion of the thermally sensitivematerial therein. This, of course, constitutes no part of the presentinvention but is noted as of interest.

It will herein be understood that these embodiments of the inventionhave been used for illustrative purposes only and that variousmodifications and variations of the present invention may be effectedwithout departing from the spirit and scope of the novel conceptsthereof.

What is claimed as the invention:

1. A snap action switch mechanism comprising a mounting member, a pairof transversely spaced brackets afiixed to said mounting member,contacts on each of said spaced brackets, a resilient contact bladedisposed intermediate said spaced contacts, an actuator lever pivotallymounted on said member, biasing means interconnecting said lever andsaid blade for selectively snapping said resilient contact blade towardone of said spaced contacts, and means comprising an extension from saidlever engageable with said resilient contact and guided within at leastone of said brackets operable to prevent engagement of said resilientcontact with one of said spaced contacts even though said resilientcontact is biased toward said one of said spaced contacts and away fromthe other of said spaced contacts.

2. A snap action mechanism comprising a mounting member, a resilientblade mounted on said member, an actuator lever pivotally mounted onsaid member, resilient means interconnecting said lever and said bladefor biasing said blade selectively toward one of two opposed extremepositions as a function of the pivoted position of said lever, and meanscomprising an extension from said lever engageable with said resilientblade to hold said resilient blade in an intermediate position betweenthe two opposed extreme positions of said blade.

References Cited in the file of this patent UNITED STATES PATENTS2,586,075 Miller Feb. 19, 1952 2,783,323 Jeffrey Feb. 26, 1957 2,792,466Raney May 14, 1957 2,798,127 Roeser July 2, 1957 2,846,538 Hager Aug. 5,1958 2,872,540 Hager Feb. 3, 1959 FOREIGN PATENTS 490,372 Germany Jan.30, 1930

2. A SNAP ACTION MECHANISM COMPRISING A MOUNTING MEMBER, A RESILIENTBLADE MOUNTED ON SAID MEMBER, AN ACTUATOR LEVER PIVOTALLY MOUNTED ONSAID MEMBER, RESILIENT MEANS INTERCONNECTING SAID LEVER AND SAID BLADEFOR BIASING SAID BLADE SELECTIVELY TOWARD ONE OF TWO OPPOSED EXTREMEPOSITIONS AS A FUNCTION OF THE PIVOTED POSITION OF SAID LEVER, AND MEANSCOMPRISING AN EXTENSION FROM SAID